A 20p difference on one packet of cereal will not transform your budget. But a cheaper cereal, pasta, nappies, cleaning spray, yoghurt and frozen veg can make a real difference when they are repeated in every weekly shop. To compare supermarket own-brand prices properly, look beyond the shelf label and assess the products your household buys again and again.

Own-brand ranges are often where supermarkets compete hardest. They can offer strong value, but the lowest headline price is not always the cheapest choice for the amount you receive, the quality you need or the journey required to buy it. A few quick checks help you keep more control of your food budget without filling the trolley with products that do not work for your household.

How to compare supermarket own-brand prices fairly

Start with a realistic basket, not a single item. One supermarket may sell cheaper baked beans, while another is better value for cupboard staples, fresh produce or children’s lunchbox food. Comparing only one product can point you towards a shop that costs more overall.

Choose the items you buy most often and list the usual quantity. Include the essentials that drive your weekly spend: bread, milk, eggs, fruit, vegetables, cereal, pasta, rice, meat or meat alternatives, toiletries, household cleaning products and packed-lunch items. If you have a baby, pets or dietary requirements, include those regular costs too.

Then compare like for like. A supermarket’s standard own-brand pasta should be compared with another standard own-brand pasta in a similar pack size, rather than a premium range or a branded product on a temporary offer. The aim is not to prove one supermarket is always cheapest. It is to find the lowest sensible cost for the products you actually use.

Keep a note of prices for a few shops. Prices and promotions change, and a supermarket that is cheapest this month may not stay that way. A simple running list gives you a more useful picture than relying on a single visit.

Check the unit price, not just the pack price

The unit price is one of the quickest ways to spot a misleading comparison. It is usually shown in smaller print on the shelf edge as pence per 100g, per kilogram, per litre, per wash or per roll. This figure shows what you are paying for the quantity inside.

A 500g pack of own-brand cheese may look cheaper than a 750g pack, but the larger pack could cost less per 100g. Equally, the bigger option is only better value if you will use it before it goes off. Throwing away food removes any saving.

Unit pricing matters particularly for concentrated washing-up liquid, laundry products, coffee, cereals, snacks, cheese, yoghurt, toilet roll and multipacks. Pack designs can make sizes look similar when the contents are not. Checking the unit price takes seconds and prevents a higher-cost item slipping into the trolley because it has the lower sticker price.

For products sold by count, such as bin bags, nappies, dishwasher tablets or toilet roll, compare the cost per item or per use. A larger pack may contain fewer sheets, smaller bags or less absorbent rolls. The best deal is the one that lasts longest at the lowest usable cost.

Separate everyday prices from short-term offers

Promotions can reduce a shop total, but they can also make price comparisons confusing. A temporary loyalty price, multibuy or introductory offer may be excellent value if it is for something already on your list. It is not a saving if it encourages you to buy more than you need.

Before choosing a supermarket based on an offer, check three things: the normal price, the promotion end date and whether you would buy that quantity anyway. This matters with items such as cereal, fizzy drinks, crisps, toiletries and freezer food, where multibuys are common.

An own-brand product at its regular low price is often easier to budget around than a branded product that is cheap only with a card or only for one week. Regular prices help households plan. Offers are useful extras, not a reliable foundation for a weekly food budget.

If you use a supermarket loyalty scheme, include the member price in your comparison only when you are happy to use that scheme every time. Otherwise, compare the standard price. That keeps your estimate honest and avoids a surprise at the till.

Compare quality where it affects waste and repeat buying

Own-brand does not mean identical. Supermarkets usually sell value, standard and premium own-brand tiers, and the cheapest tier may not suit every product. A lower-priced washing-up liquid that needs twice as much per wash, or a loaf that goes stale before the weekend, can cost more over time.

Use your own household’s experience. If everyone eats the standard own-brand cereal and enjoys it, there is little reason to pay extra. If a cheaper coffee, pet food or nappy does not meet your needs, forcing the switch can create false savings and frustration.

A practical approach is to test one replacement at a time. Try the lower-cost own-brand version of a regular purchase, then decide whether it earns a permanent place on your list. Staple foods such as tinned tomatoes, pasta, flour, oats and frozen vegetables are often easy places to start. Products where performance or preference matters more can stay on your usual list.

Factor in delivery, travel and fuel costs

The cheapest grocery basket is not always the cheapest shopping trip. A lower-priced supermarket further away can lose its advantage once petrol, parking, public transport or delivery charges are added. This is especially relevant if you are making a separate journey for a handful of items.

Work out the total cost, not just the receipt. If splitting your shop across two supermarkets saves £4 but adds an extra drive and 40 minutes of your time, it may not be worthwhile. If the saving is £15 on a larger monthly stock-up, the calculation changes.

You can keep this simple. Use one supermarket for the main weekly shop, then only make a second stop when the price difference on planned items clearly exceeds the travel cost. Checking nearby fuel prices before you set off can also stop grocery savings being absorbed by a more expensive fill-up.

PricePAL Compare can help make these decisions faster by putting grocery and fuel price checks into the same routine. Use price information before leaving home, and scan barcodes in store when you need to check whether a product is genuinely cheaper elsewhere.

Build a repeatable lower-cost shopping routine

The most effective comparisons are the ones you can repeat without spending hours researching. Keep a saved list of your core products and update it when prices move or your household’s needs change. That gives you a clear baseline for judging whether a deal is worth switching for.

Buy non-perishable items in larger quantities only when the unit price is lower, the offer is genuine and you have room to store them. For fresh food, plan around meals you will actually cook. A slightly higher price for the right quantity is better than a bargain that ends up in the bin.

It also helps to leave some flexibility in the basket. If your preferred own-brand chopped tomatoes are more expensive this week, another supermarket’s equivalent may be a straightforward swap. If the price difference is small and a product is a household favourite, keeping it may be the sensible choice. Saving money every week is about better decisions, not perfection.

The next time you shop, pick five regular own-brand products and compare their unit prices, normal prices and pack sizes. Small checks on the items you buy repeatedly can turn price awareness into savings that stay with you week after week.